It is a consistent drive of the automotive industry as a whole to reduce the overall complexity of motor vehicles. Original Equipment Manufacturers (OEM) and suppliers alike seek to reduce the total amount of parts that comprise a particular vehicle build which usually can exceed 5000. It is a further objective of OEM's to improve the overall vehicle packaging constraints so as to provide aperture with either more interior room or ground clearance. Consisting contemporaneously with these drives is the desire to improve consumer satisfaction and occupant safety.
Some of these objectives can be met by enhancing the exhaust systems and collision of a vehicle. In particular, by integrating the muffler into the rear bumper system of a vehicle there is a reduction in the amount of parts needed for vehicle assembly which reduces production time. Vehicle packaging constraints are also improved by moving the muffler up away from the lower portion of the vehicle into the bumper region thereof.
It is an object of a prior invention, U.S. Pat. No. 5,726,398, to achieve these objectives through integrating the muffler into the bumper system. However, the muffler components of the prior invention are those of a traditional method of producing mufflers housed within the bumper. Therefore, the muffler portion of the combined systems is more complex than need be. There continues to be a need in the art to provide a simple, cost effective, and compact way of providing a truly integrated bumper and exhaust system.
It is an object of the present invention to achieve the objectives set by OEM's and sub-suppliers alike both by fully integrating the muffler into the bumper system as well as designing a simpler, longer lasting muffler system itself. This is achieved via an extruded skeleton acting as a muffler. The extrusion process used to form the skeleton creates gas exhaust flow channels along the length of the muffler. These gas exhaust channels incorporate exhaust passage holes for allowing the flow of exhaust gases between channels. Exhaust inlet and outlets are formed on opposing sides of the extruded skeleton which allow for exhaust gases to enter and exit the muffler respectively.
Several advantages of the extruded skeleton formation are readily apparent. Initially, the near square form of the exhaust chambers allow for more efficient utilization of space reducing the overall size of the muffler, thus lowering packaging needs. Additionally, active or semi-active noise attenuation components can be easily integrated into the flow chambers of the extruded skeleton. Traditional muffler construction employs thin-walled sheet metal which is susceptible to fatigue and corrosion. The extruded skeleton, being formed as such, allows for greater wall thickness, improving the wearability and corrosion characteristics of the muffler. Finally, this method of producing the muffler system allows for a more rigid structure than that of traditional muffler systems. This added rigidity can be utilized in several ways including crash resistance and/or improving the rigidity of the overall frame structure as the skeleton can be attached directly to the frame members.
Further areas of applicability of the present invention have become apparent from the detailed description provided hereinafter. It should be understood, however, that the detailed description and the specific examples, while indicating preferred embodiments of the invention, are intended for purposes of illustration only, since various changes and modifications within the spirit and scope of the invention will be apparent to those skilled in the art from the detailed description.